The measurement and evaluating of environmental parameters and especially the measurement of a characteristic of a surrounding atmosphere, is necessary for a variety of applications, e.g. for long-term information gathering with respect to the environment and for short-term information collection for immediate evaluation and interpretation. This is especially the case where the measurement may contain noxious, a toxic or explosive gases, such measurement being necessary in many cases for the survival and safety of personnel exposed to the atmosphere. The results of such measurements can be used to initiate or control ventilation or some other action, e.g. evacuation or rescue.
It is known to utilize at least one measuring device to measure at least one such parameter, e.g. methane concentration, for example, in subterranean sites, i.e. mine tunnels, galleries and shafts, and to store the measured values or magnitudes of the parameter in a written form with the values being introduced into a book or the like. In mining applications it is known to provide a so-called weather book in which one enters as a function of location and time the various values determined by the measurement of the aforementioned parameters so that even after a long period of time it is possible to review the measurement. The evaluating or analysis of the measured values is effected at a later time, for example using comparison tables.
In many cases it has been found that the measured and evaluated magnitudes of the environment which are obtained in the afore-described manner do not constitute or contain optimum information since the boundary conditions under which the measurements are obtained are either inexact or are insufficiently known to enable the information to be utilized. In certain cases, moreover, certain measurements are not meaningful because of the lack of other measurements. For example, physiology plays a role in the sense that the air temperature also may not be meaningful because it may be measured at a high relative humidity or a low relative humidity so that the temperature measurements are meaningful only if relative humidity is also given.
Similarly, a given gas concentration of toxic, noxious or explosive gases may be more or less dangerous depending upon other parameters of the atmosphere and other conditions.
As a practical matter, earlier methods of monitoring the various parameters of a mine or like atmosphere have proven to be unsatisfactory in that they have not supplied sufficiently clear, complete and utilizable data to satisfy the requirements for efficient mine operation and personnel safety.